It is conventional practice in plant breeding or plant advancement experiments to grow plants from seeds of known parentage. The seeds are planted in experimental plots, growth chambers, greenhouses, or other growing environments in which they are either cross-pollinated with other plants of known parentage or self-pollinated. The resulting seeds are the offspring of the two parent plants or the self-pollinated plant and are harvested, processed, and planted to continue the plant breeding cycle. Specific laboratory or field-based tests may be performed on the plants, plant tissues, seeds or seed tissues in order to aid in the breeding or advancement selection process.
Generations of plants based on known crosses or self-pollinations are planted and then tested, such as through trait purity tests, to see if these lines or varieties are moving toward characteristics that are desirable in the marketplace. Examples of desirable traits include, but are not limited to, increased yield, increased homozygosity, improved or newly conferred resistance and/or tolerance to specific herbicides and/or pests and pathogens, increased oil content, altered starch content, nutraceutical composition, drought tolerance, and specific morphological based trait enhancements.
Often, seeds having desirable characteristics are produced commercially for sale in the marketplace. In such instances, quality control tests, such as genetic and trait purity tests, may be conducted to determine that the seeds indeed comprise the advertised genetic composition. In many instances, a certain number of seeds may be sampled from each bag of seeds produced. For example, it is not uncommon to test approximately one hundred seeds from each production bag in order to verify the genetic composition of the seeds from the bag. For some seed types, such as those in large production, this can translate to over one million individual seeds to be sampled, prepared, and genetically tested.
In order to test the genetic composition of the seeds, the whole seed, representative samples of the individual seeds themselves, or representative samples of the plants that develop from the seeds are gathered. For example, according to one method for acquiring a prepared representative sample, a hole is drilled in a small location on the seed and the debris from the seed is removed. The debris is then transferred to a test tube or other container and analyzed. Another method is described in V. Sangtong, E. C. Mottel, M. J. Long, M. Lee, and M. P. Scott, Serial Extraction of Endosperm Drillings (SEED)—A Method for Detecting Transgenes and Proteins in Single Viable Maize Kernels, Plant Molecular Biology Reporter 19: 151-158, June 2001, in which a hand-held rotary grinder is used to grind off so-called “drillings” from each kernel so that the drillings may be analyzed.
In another method of obtaining a representative seed sample, the seeds to be sampled may be grown out, such as by placing a number of individual seeds on a paper towel that is then rolled up and placed in a growth chamber for a certain period of time. Once the immature plants have emerged, samples of the coleoptiles are taken. Another method involves obtaining an unprepared sample, such as a leaf tissue sample, a portion of grown out coleoptiles, a laser cut sample, or a sample cut by clippers, and placing the unprepared sample in corresponding vials that are placed in a laboratory grinder, such as the Geno/Grinder 2000 available from SPEX Certiprep of Methuchen, N.J. Ball bearings are used crush up the seeds into a powder which can then be tested. U.S. Patent Publication No. 2008/0113367, which is assigned to the assignee of the present application, and which is incorporated herein by reference in its entirety, describes yet another method of obtaining a representative sample of seeds through removal and collection of tissue using a hand-held and manually-operated tool having one or more cutting edges.
The above methods of obtaining seeds samples and processing them for genetic analysis are extremely time consuming, expensive, and involve numerous manual processes. In addition, extreme care and diligence must be employed in order to avoid contamination and cross-contamination of the samples. Also, in many instances the success and effectiveness of these methods depend heavily on the attention and accuracy of the technician. Furthermore, the above methods are not economically practicable for those situations related to the production of commercial seeds.
As a result, there is a need for a system and method for preparing a sample of individual seeds for use in genetic and trait purity testing and the like. In various embodiments, the system and method should allow a large number of seeds to be sampled in a relatively small amount of time and should maintain a particular throughput level for efficiency purposes. It should reduce or virtually eliminate contamination and cross-contamination between samples and should be flexible so as to accommodate the need to sample large numbers of seeds.